RGH Zypher Slow Cold Boot / Fast Warm Boot

[WNYConsoles]

I have a customers Zypher which after many hours of tinkering with I have determined it is suffering from the Cold Boot issue and I was wondering if anyone has any recommendations on how to fix or help this issue.

Firstly, the issue is not soldering, ECC, or FB image, I have done dozens of Cool Runner installs.

Secondly, I have wired the board to make sure there are no interference issues, flashed nand with Xenon.elf, and using FB 14699

The only thing I have not tried at this time is using a different Cool Runner board, however I do not feel that could be the issue as the board boots perfectly once it is warm.

If anyone has any ideas or recommendations I would greatly appreciate it.

Thank you

 

[Martin C]

Can you confirm what cold boot/warm boot is referring to?

Is it the temperature of the CPU?

If so, you may need to reflow the CPU as it could be a cold solder joint.

 

[WNYConsoles]

When the unit has been running for a few minutes attempting to glitch, once warm, if you power cycle it will boot nearly instantly. Additionally if you power cycle while its warm it boots.

I do not believe it to be hardware related as it boots fine with stock nand.

Any other ideas?

 

[Martin C]

It shouldn't really matter as when the glitch-cycle is underway, you're slowing the CPU clock speed down. This isn't something you would normally do on a retail unit.

However it's possible that the heat is decreasing resistance, making it work. You may want to try playing around with CPU_PLL_BYPASS capacitance.

 

[WNYConsoles]

Any recommendations for type of capacitors to put on PLL? Right now I have tried 1x and 2x 68nF 50V on Ground/PLL with no effect.

 

[chriss179]

Same problem. And probarbly many with you and me..

When cpu is hot (i put a credit card in wind tunnel to prevent air from cooling the cpu while the gpu is kept cold. then it boots after cpu gets +70-80C) the xbox boots AT ALL!!! Below that no boot.. EVER!

I have 680pF 20V Capacitors (ceramic) here.. But when using them no glitching occurs anymore.
Also tried to cut the cpu_reset to 32 and 50cm. Made sure all the cables went via underside of the board under the gpu and cpu unto their designated areas to keep away from any coil posible...

retail nand boots immediatly, glitch nand boots ONLY when cpu is REALLY hot.

Zephyr board v2.0 14699 retail and glitch.

 

[Martin C]

try a 680pF between A and GND and a 470pF in line with CPU_RST.

 

[diaboliq20]

quick question for martin,as I am working on a troublesome Zephyr, and this thread caught my eye - it will not glitch and boot to xell (I have my own thread on this matter though, so please don't think I'm trying to hijack lol) - I have installed the standard cap, and wondered if the additional 470pF you mentioned may help - I am going to have a quick try with a "warmer chip" just in case, but it would seem very odd wouldn't it - interesting thread, and I hope the OP keeps us updated

 

[Martin C]

The config I suggested has worked with those where the normal 68nF between A and GND haven't.

It can't be a coincidence that all zephyrs seem to fall foul of this, however I've had a couple my way which glitched instantly. I'll put it down to luck.

The CPU in the Zephyr is the same as the Xenon (IIRC) so wonder if this has relevance.